Forced driver updates – potential instability
Forced updates don't apply in production environments - the Enterprise license allows you to defer the compulsory ones for 6 months and refuse the non-compulsory ones. This is pretty much exactly how we used WSUS anyway for the last decade or so.
Windows as a Service – meaning Windows 10 will never be final/stable
SaaS models are popular with Enterprise clients, that's why Microsoft are adopting it and why 'cloud-based' is a thing. I personally despise not knowing precisely where my data is, but many of the guys who control the checkbooks don't mind.
Firstly, this won't get past my firewall to Microsoft unless I decide I want it to. Secondly, I practice much, much more invasive data collection on my users already as a matter of course. The do not have personal privacy when they are using our machines. I monitor all their web traffic (which isn't noticeably higher on Win 10 clients), they cannot delete their browser history, I arbitrarily control what they're allowed to look at anyway, hell, I even know what they're looking at on their personal mobiles if it goes over our guest wifi. I log everything they're doing. I could even activate keyloggers on their systems if I saw fit. And I'm relatively liberal in this regard compared to some of my colleagues.
Your employer probably has a full Computer Use policy somewhere. It's often worth giving it a read and realizing just how heavily scrutinized you are (and how quickly your employer will dump all possible responsibility on you and shop you to the police).
Not faster than Win 7 without hibernation/fast start enabled
Basically untrue, provided you know how to configure Windows properly. Win 10 comes out-of-the-box with around 115 scheduled tasks. Enterprises will disable almost all of them.
Many more system services running, more disk and network activity, bigger attack vector
Nope, also pretty much untrue. Win 7 had a similar number. Win 10 also just has better security in general from the kernel up.
Not suitable for production environment – reasons listed above
Not so. We have about 8 machines running Win 10 on our environment currently, and they're not problematic (which is somewhat surprising for an MS OS that's under a year old).
Add rude and reckless update policy for Win 7/8 users
Not for our clients. MS is NOT giving Win 10 away to enterprises. We have to pay for it if we want it. It's pushing it out to end-users for free, because then they'll learn how to use it at home and so it encourages us to give MS a huge amount of money to buy software that our users are comfortable with. But we're not going to buy 15,000 home licenses. We're going to buy enterprise license agreements at huge prices, which have dozens of extra features which simply aren't included in Home.
So what does Windows 10 bring to the table:
Cortana – (I have not tried it)
Direct X 12 is nice, but so far only a couple of games use it
Desktop switcher – nice but not a killer feature
Various fixes but pales in comparison to introduced problems
Enterprise doesn't give a toss about any of that crap. You're thinking about it from the user's point of view, rather than the CIO's. We do, however, care about a lot of stuff you missed, including:
Hyper-V (I no longer need to pay VMWare a thousand quid a year for the right to run VMs on my desktop; I could even make my users run through it, giving huge security and maintenance benefits)
Powershell 5.0 (mmmmm, powershell with a built-in apt-get - yes, you can install it on win 7 and win 8, but many functions don't work)
BYOD support (which is awesome in Win 10 compared to Win 7 or 8)
Windows Enterprise Store, which will allow me to remotely roll out software to a thousand devices quickly and easily.
Excellent Azure integration (for those in Azure AD).
Better SCCM integration.
Better intergration with the forthcoming Server 2016 (which is likewise a huge improvement over 2008, unlike server 2012)
Now, some of these were around for Win 8, but we don't like Win 8 because the UI was awful for users (I personally suspect Metro was the only real reason Win8 sank). They were lovely toys being handed to us in a pile of dog poop. Win 10 is not a pile of dog poop, so we can unwrap the lovely lovely toys and make proper use of them. The automation level that admins can enjoy with Win 10 clients is enormous. Combine that with half a decade's worth of improvement to underlying processes, and it's actually a very tempting OS from the IT dept's point of view - it's close enough to 7 that users can understand it, it's hugely beneficial to admins, and it's futureproof where Win 7 is growing long in the tooth (and no, we're not gonna be switching anyone to Linux in droves, even if the Russians and the Chinese are).
You're not gonna see Enterprises adopting it on a large scale until maybe May or June, for a few reasons: 1), we have to pay for it. 2) Certs for it aren't out yet. 3) We'll wait for the new financial year. 4) IT departments want to see that something has been out and working for at least 6 months. But yeah, Win 10 use is already at around the level of Win 8+8.1 (i.e., more than all linux distros and Mac OS), and yeah, it's good enough that enterprises are going to go for it.
Your reasoning goes wrong because you made the assumption that Windows is written for users. It's not, and it hasn't been for years. It's written for IT purchasers, which isn't end-users. We're a Microsoft house because a full MS stack gives me, the sysadmin, WAAAAAAAAAAY better control over what my userbase are doing than any other option. I could shunt everyone over onto a Linux distro and not have to pay for licenses (as I did with enough of my server farm), but from the point of view of the network as a whole, keeping everyone on some in-support variant of Windows is the way to go even if we have to pay through the nose to do it. Linux doesn't offer the same degree of network-level control as windows+sccm+powershell+AD+GP, and I'd have to pay Linux admins twice as much as I pay Windows techies which really kills the saving from license costs. As for Apple, their stuff is an absolute joke in the enterprise.
As a home user, I agree with most of what you say about win 10. As a sysadmin, not so much really.